The closed border near Shenzhen is Hong Kong's version of the final frontier. For decades, access to this strip of land has been carefully restricted and, until 1994, a midnight curfew was imposed. It is a throwback to a bygone era. Concerns about illegal cross-border activities led to the zone, officially known as the Frontier Closed Area, being given this special status. First it was gunrunners during the Korean war, then illegal immigrants from the mainland. The sealing off of the area has had unintended - and welcome - consequences. One has been that the zone has escaped the ravages of development responsible for swallowing up - and concreting over - so many other parts of Hong Kong. Many residents have continued to live in the village of Shataukok, which straddles the border. But much of the area is jungle. These ecological 'hot spots' have become home to an astonishing variety of wildlife. The extent of these floral and faunal treasures was revealed yesterday in a study by the research group Kadoorie Farm and Botanic Garden. It found that many rare species of plants, mammals, birds, reptiles, butterflies, dragonflies, moths and fish inhabit the zone's woods, streams and hills. The presence of many of them came as a surprise. Take the animals captured on film by infrared cameras set up by the group. Few would have imagined that the crab-eating mongoose and yellow-bellied weasel were among those counting themselves as Hong Kong residents. The orange-headed thrush, mountain wolf snake and the large bent-winged bat were also found. The survey provides a detailed snapshot of the diverse flora and fauna thriving in the restricted area. It underlines the high ecological value of the site. If the first step towards protecting our environment is to be aware of precisely what it is that needs to be preserved, the study provides valuable insight. But as those who carried it out are only too well aware, much more needs to be done. The process of integration between the mainland and Hong Kong has made the area a target for all sorts of redevelopment schemes. An expressway, a new town, an industrial centre, and a hub for eco-tourism are among the proposals which have been floated for the zone and the surrounding area. As Shenzhen expands on one side and Hong Kong on the other, it is in danger of being squeezed. Our ecological gems are under threat. Concerns raised by the group should be taken seriously. Key ecological hot spots should be protected. The call for a careful approach to be adopted towards development of the area, involving consultation with all interested parties, should also be heeded. The study has provided fresh evidence of the natural treasures in our midst. Everything possible should be done to ensure they do not disappear.